Continuous-current dynamo.



PATENTED JUNE 7, 1904. B. J. JAVAUX & A. M. L. BARBOU.

CONTINUOUS CURRENT DYNAMOQ APPLICATION FILED JAN. 28. 1903.

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UNITED STATES PATENT OEEicE.

EMILE JULIEN J AVAUX AND ALFRED MARIE LOUIS BARBOU, OF PARIS,

FRANCE.

CONTINUOUS-CURRENT DYNAMO.

SPECIFICATION forming part of Letters Patent No. 761,682, dated June '7, 1904.

Application filed January 28, 1903.

To all whom it may concern.-

Be it known that we, EMILE J ULIEN J AVAUX and ALFRED MARIE LoUIs BARBOU, directors of the Socit Gramme, citizens of the Republic of France, residing at No. 20 Rue dHautpoul, Paris, in the Republic of France, have invented certain new and useful Improvements in Continuous-Current Dynamos, of which the following is a specification.

This invention relates to improvements in continuous-current dynamos, and has for its object to provide means for controlling the magnetic resistance or reluctance of the magnetic circuits by means of thin bars or rods of iron adapted to be parallelly displaced with regard to the armature-axis in holes or grooves formed in the pole-pieces in direct proximity to the bore. By this means the strength of the magnetic flux can be altered, and consequently the inductive reaction, so that the speed of the machine can be altered without difliculty within very wide limits.

The controlling devices hitherto known based on the insertion of variable masses of iron into magnetic circuits have considerable disadvantages. Thus, for instance, the displacement of a heavy iron core arranged inside a pole-piece entails magnetic leakage and produces a very considerable displacement of the field between the magnet and the armature, so that frequent adjustment of the brushes in accordance with the displacement of the field is rendered necessary.

Our invention is illustrated in the annexed drawings, in which- Figure 1 is a longitudinal sectional View of our improved controlling arrangement adapted to be regulated by hand. Fig. 2 is a front view of same. Fig. 3 is a cross-section of same through line A B ofFig. 1, the core being removed. Fig. 4 is a longitudinal sectional view of our arrangement adapted to be automatically regulated.

The pole-pieces a of the dynamo are provided with apertures b in such a manner that the section of passage for the magnetic flux is considerably reduced. The said apertures can consist of holes of circular or any other shape extending from one side of the pole-pieces to Serial No. 140,927. (No model.)

the other, and they can be arranged in greater or smaller distances from each other, but always in close proximity to the bore. In the holes 5 are adapted to slide with slight friction iron bars (Z, of the same shape as the holes. These bars may be inclosed in non-magnetic material to prevent their adherence, as shown at d in Fig. 3. According to the extent to which these iron bars are inserted into the apertures, the section of passage for the magnetic flux is increased or reduced and the magnetic resistance or reluctance of the circuit consequently altered.

The insertion of the bars (Z into the polepiece apertures can be effected by hand or automatically.

Figs. 1 to 3 illustrate means for simultaneously displacing the bars by hand by means of ahand-wheele. For this purpose the bars (Z are mounted on a segmental bar 0, to which are secured screws it, engaged in the hubs of pinions g, gearing with a toothed wheel f, made integral with the hand-wheel c. The pinions g are mounted on their bearings in such a manner that they are free from rotating, but cannot move lengthwise. It may thus be seen that by turning the hand-wheel c the screws h, and consequently the segmental bars 0, together with the bars (Z, are moved lengthwise, causing thereby the bars (Z to be inserted to a greater or less extent in the polepieces.

Fig. 4 illustrates means for automatic adjustment for the purpose of maintaining a constant electromotive force in the case of a dynamo driven at variable speed. In this case the segmental bars 0, carrying the bars (Z, are connected, by means of rods and a crossbar j, to the sleeve of a centrifugal governor 7 which regulates automatically the insertion of the bars into the pole-pieces. When the speed the bars d out of the pole-pieces. The electro- 9 5 motive force, which has augmented accordingly, is thus diminished and brought to its normal value. When, on the contrary, the

speed of the machine diminishes, the bars (Z are inserted to a greater extent in the polepieces, and the eleetromotive force is aug mented till it reaches its normal value.

ith the arrangement illustrated the re action on the armature is inodilied in the same ratio as the magnetic flux, and this takes place without causing sparking at the brushes within very wide limits with the same output of power. The speed of the machine can be trebled or quadrupled without causing defectiveaction.

Having now described our invention, what we claim as new, and desire to secure by Letters Patent, is-

1. A continuous-eurrent dynamo comprising pole-pieces provided with holes parallel with regard to the armature-axis and in close proximity to the bore, in combination with iron bars adapted to beinserted into theholes of the pole-pieces, and means for inserting said bars into said holes to a greater or less extent, substantially as and for the purpose set forth.

2. A continuous-current dynamo comprising polepieces (t provided with holes parallel with regard to the armature-axis and in close proximity to the bore, in combination with iron bars (Z adapted to be inserted into the holes of the pole-pieces, segmental bars 0 on which said bars are mounted, screws It secured to said segmental bars, piuions 1 engaging said screws, and a hand-wheel made integral with a toothed wheel f gearing with the pinions g, substantially as and for the purpose set forth.

In witness whereof we have hereunto set our hands in presence of two witnesses.

Jlilllhhl .lUlillfiN .IAYAUX. AlJFliElbMdlilE LOUIS llAllliUU.

\Vitnesses:

ANTOINE LAvoIX, AUG'Us'IUs E. INGRAM. 

